WIRELESS POWER TRANSMITTING UNIT, WIRELESS POWER RECEIVING UNIT, AND CONTROL METHODS THEREOF

A control method of a wireless power receiver is provided, which includes wirelessly receiving a first power from a wireless power transmitter; based on the received first power, loading a first communication stack from a memory stored in a communication module of the wireless power receiver; establishing a communication connection with the wireless power transmitter based on the first communication stack; wirelessly receiving a second power from the wireless power transmitter; based on residual capacity of a battery of the wireless power receiver exceeding a minimum power threshold according to the received second power, determining to re-initialize the communication connection with the wireless power transmitter; transmitting a message including a time period required to complete at least one procedure for re-initializing the communication connection with the wireless power transmitter; and wirelessly receiving the second power from the wireless power transmitter while re-initializing the communication connection with the wireless power transmitter.